upgraded Roslyn to 3.6.0

[filipw]

I noticed that Roslyn 3.3.1, which is almost 1 year old, is still in use. This PR updates to 3.6.0 which aligns with VS 2019 16.6

sibling PR to microsoft/qsharp-compiler#499
cc @bettinaheim

[bettinaheim]

@filipw I pushed the package with the corresponding change on the compiler repo to our alpha channel. In order for this PR to work, you would need to pick up that change; i.e. the I believe 8 uses of the Microsoft.Quantum.Sdk need to point the version 0.11.2006.3017-alpha, as well as the one package reference to the Microsoft.Quantum.Compiler in the C# generation.
Do you want to give this a go? Alternatively I am happy to do it if I may push to your branch?

[filipw]

thanks - I pushed the change here.
Overall I was genuinely trying to help but I now see that the required coordination between the two repos is only causing you extra headache instead of helping 😅

[bettinaheim]

@filipw You are definitively helping!
It's great to have an additional set of eyes on this to notice things like old packages! :) Sorry for the hassle regarding coordination between the compiler and runtime repo for certain things.

[bettinaheim]

Need to be merged at the same time as microsoft/qsharp-compiler#499.